Device for scanning bar codes

ABSTRACT

A scanning device for recognizing and reading bar codes is configured to have a housing that can be mounted on a scanning surface or beneath the scanning surface. The housing contains an internal scanning face unit, which includes a source of laser light, a rotatable polygonal mirror for reflecting the laser light, a plurality of fixedly disposed flat mirrors and a pick-up element for detecting radiation deflected by the bar code. This internal scanning unit can be arranged within the outer housing in four different positions, thereby creating greater flexibility with respect to the mounting of the overall housing.

BACKGROUND OF THE INVENTION

At an increasing number of retail outlets use is being made at thecheckout of scanning devices for bar codes which are arranged eitherlying in a table top or standing thereon. In the case of devicesarranged lying in a table top the object to be paid for is moved overthe transparent plate with the bar code downward whereby the transparentplate must be replaced frequently due to scratches.

In the case of scanning devices in standing position this problem doesnot occur. Here however the problem does occur that the space for such ascanning device in standing position is usually limited, particularly inthe case that an existing scanning device must be replaced by a newversion with improved operation. Scanning devices of the prior art arefurther designed in accordance with the desired direction of the objectsfor moving therealong, i.e. from left to right or from right to left.

SUMMARY OF THE INVENTION

The present invention provides a device for scanning and/or recognizingbar code, comprising:

a housing mountable standing in or on a surface; and

an internal unit comprising a source of laser light, a rotatablepolygonal mirror for reflecting the laser light, a plurality of fixedlydisposed flat mirrors and a pick-up element for picking up radiationscattered by the bar code, wherein the internal unit is placeable in thehousing in two or more positions.

The scanning device according to the present invention can be applied inhighly diverse existing situations and can be built into most existinglocations owing to the possibility of changing the direction of the scanlines by rotating the internal unit through one or more quarter-turnsand also owing to the compact dimensions thereof.

The rotatable polygonal mirror and the lying mirrors are preferablydisposed relative to each other such that scan lines are projectedoutward in five different directions through a transparent plate of thehousing. The length of the scan lines therein extends practically overthe full width of the window.

The present invention further provides a module for a scanning devicewhich is sealable in a dustproof manner and comprises a source of laserlight, a rotatable polygonal mirror for reflecting the laser light, aplurality of fixedly disposed flat mirrors and a pick-up element forpicking up radiation scattered by the bar code and an inner housingwhich is arrangeable in an outer housing of random dimensions greaterthan the inner housing and which seals the components of the internalunit in dustproof manner.

This module can be coupled to an application specific to a relevantcustomer, for instance a manufacturer of cash register systems; in thatcase a specially tailored interface can also be designed for thisapplication. This module can also be built into many existing housingsowing to the compact dimensions.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, features and details of the present invention willbe elucidated on the basis of the following description of a preferredembodiment thereof with reference to annexed drawing, wherein:

FIGS. 1A-1L show schematic front views of a possible method of arranginga preferred embodiment of a device according to the invention;

FIG. 2 shows a front view of the device of FIG. 1;

FIG. 3 shows a cross-sectional view of the device of FIGS. 1 and 2;

FIG. 4 shows a top view of a fixing element for fixing the device ofFIGS. 1, 2 and 3;

FIG. 5 shows a partly exploded and broken away view of diversecomponents of the device of FIGS. 1-4;

FIG. 6 shows an exploded view of the device according to FIGS. 1-5;

FIG. 7 is an exploded view of the internal unit of the device accordingto FIGS. 1-6;

FIG. 8 is a schematic view of the radiation beams from the device shownin FIGS. 1-7; and

FIG. 9 is a view in perspective of the adjustment of a focussing elementof FIG. 8.

DETAILED DESCRIPTION

FIGS. 1A-1D show a device 1 according to the present invention, a lowerpart 2 of which is situated below the upper level of a table top T, isfor instance flush-mounted therein. Situated in the lower part 2 is aboard with digital electronics and an interface connected to an electriccable which extends downward through the table top. In FIGS. 1E-1H thedevice 1 is placed on the table top with the lower part 2, whileaccording to FIGS. 1I-1L the device 1 is tilted, i.e. the lower part 2now extends sideways. Also in this tilted position of device 1 the cablefor electrical connection is preferably carried downward through tabletop T. The tilted position according to FIGS. 1I-1L, in addition to theflush-mounted position according to FIGS. 1A-1D have the advantagerelative to the positions according to FIGS. 1E-1H that an object forscanning does not have to be lifted from the table top but has only tobe moved over the table top with the bar code directed toward device 1.In FIGS. 1A-1L is shown a rotatable quadrangular mirror 3 as well asscan lines S which are projected outward at at least five differentangles in sets of four lines each. The scanning pattern S as drawn isvisible as laser lines on the transparent plate of the device.

As can be seen in FIGS. 1A-1D, the internal unit of the device as isdesignated using the position of the quadrangular mirror 3 can, in eachposition of the housing, be arranged therein in four differentpositions, whereby the scanning pattern is likewise adapted to thewishes of the user, for instance whether the objects are moved from leftto right or from right to left or otherwise.

In FIG. 2 is shown the quadrangular mirror 3 which is preferably formedby a plastic element with mirror surfaces vapour-deposited thereon, inaddition to fixedly disposed inclining mirrors 4, 5, 6 etc. Thetransparent plate 7 through which the view is taken is provided with aclear laser light-transmitting part opposite the mirrors and a dark part8. The transparent plate 7 preferably takes a single form and isprovided with a scratch-resistant coating.

Further designated in FIG. 3 is a board 9 which is situated in the lowerhousing part 2. The rotating mirror 3 and a plurality of flat mirrorsare also shown.

FIG. 4 shows a mounting or console element 10 provided with a pluralityof holes 11, 12, 13, 14, 15, 16, 17 and 18 for passage of mountingelements. A central opening 19 is the gate which results duringinjection moulding of the console element.

In FIGS. 5 and 6 can be seen that the holes for the mounting elements inconsole element 20 extend through respective standing parts 21, 22 ofdovetail-like form into lower dovetail-like grooves 23 and 24 arrangedin housing 25. When device 1 is mounted in the position shown in FIGS.1E-1H, the holes 11, 14, 15 and 18 are used for screws B and themounting element 20 is screwed onto the table, whereafter housing 25 ispushed thereon. Finally, the pushed-on position of housing 25 is fixedusing a closing cover 26 of L-shaped cross section which also fixes thehousing 25 in rearward direction. Closing cover 26 is provided withcounter elements which fit into dovetail-like grooves 40 and 41 as wellas pins with a thickened end which can be snapped into oval holes inhousing 25. A flexible frame 27 is glued against frame 28. Inside frame27, the transparent plate 7 is fitted and glued against frame 28. Frame28 is snapped fixedly onto inner housing 30. Preferably situated betweeninner housing 30 and frame 28 is a labyrinth seal for dustproof sealingof the inner housing in which the mirrors and the like are situated.

Frame 27 is fitted fixedly into housing 25 during assembly. The rearplate 31 is provided with hooked ends 32 so that plate 31 can be fixedin a manner not shown with a single screw in order to further simplifyassembly. In the embodiment shown in FIG. 5 an electric cable (notshown) for power supply and other electrical signals can be guidedthrough an opening 33 in the outer housing to a board 9 on which digitalelectronics are situated.

In the flush-mounted positions shown in FIGS. 1A-1D use can be made ofscrew bolts B which are screwed into angular counter elements arrangedin openings 12, 13, 16 and 17 of console 20.

Both in the position shown in FIG. 5 and in the tilted position in whichthe grooves 40 and 41 engage on the standing parts 21 and 22, the recess33 is situated close to the table top, in an opening of which the cablescan then be carried away.

With reference to FIG. 7 and also to FIG. 3, it is of further importanceto note that a cable 51 is connected to a board 50 on which the laserlight source and the receiver for the reflected laser light aresituated, this preferably being a flat cable which must be connectablein all positions shown to the board 9 on which the digital electronicsis situated. Arranged for this purpose on board 9 (see also FIG. 6) isan electrical connection 52 consisting of two connectors, so thatcontact with this connection is ensured in any rotated position of theflat cable.

Further shown in FIGS. 7, 8 and 9 is a focussing element 54, whichserves to focus scattered laser light radiation to a detector 60. Inorder to improve the efficiency (to 99.98%) use is made here of aplastic element onto which a gold layer is vapour-deposited, wherebytransmission losses such as occur in lenses are avoided. The componentsof the internal unit of FIG. 7 otherwise relate to the flat mirrors, therotatable mirror, a motor therefor, and a component 55 on which allthese elements are arranged and on which a dividing mirror 56 is alsoarranged which serves to separate the transmitted and reflected lightand which, with the exception of a passage strip for the scattered laserlight beams, is likewise provided with a gold coating.

For easy adjustment of focussing mirror 54 this latter is arranged usingat least slightly resilient rods 61, 62, while on one side a rotatableadjusting screw 64 with a slightly eccentrically arranged pin 65 isarranged through a flange 63 on mirror 54. During assembly of the deviceaccording to the present invention a screw element 64 is turned using ascrewdriver until the intensity of scattered laser light measured by thedetector is at maximum. When adjusting element 64 is turned the mirror54 is displaced counter to the spring action of rods 61 and 62.

The above described preferred embodiment of the device according to theinvention is extremely compact and provides a dense scanning pattern inall desired directions, also due to the high rotation speed of thequadrangular mirror, for instance 6,000 revolutions per minute and thespeed of the electronics adapted thereto.

The rights applied for are however in no way limited by the abovedescribed preferred embodiment of the present invention; the rightsapplied for are defined by the following claims.

What is claimed is:
 1. A device for scanning and/or recognizing barcode, comprising: a) a scanner housing fixably mountable in or on agoods-handling counter surface; and b) an single internal unit arrangedas a discrete unit within said housing and comprising i) a source oflaser light, ii) a rotatable polygonal mirror for reflecting the laserlight, iii) a plurality of fixedly disposed flat mirrors, and iv) apick-up element for picking up radiation scattered by the bar code,wherein said single internal unit is placeable in said scanner housingin two or more positions having an angular difference between oneanother of 90 degrees or 180 degrees to change scan direction orpattern, without altering position of said scanner housing with respectto said counter.
 2. The device of claim 1, wherein the internal unit isplaceable in the housing in four positions.
 3. The device of claim 1,wherein the housing is placeable in two or more positions relative tothe surface.
 4. The device of claim 1, wherein the housing can be fixedpartly flush-mounted in the surface.
 5. The device of claim 1, whereinthe housing is provided on at least two sides with one or more groovesof dovetail-shaped cross section.
 6. The device of claim 5, furthercomprising a mounting element with counter-elements fitting into thegrooves.
 7. The device of claim 1, wherein the rotatable polygonalmirror and the fixedly disposed flat mirrors are disposed relative toeach other such that scan lines are projected outward in five differentdirections through a transparent plate of the housing.
 8. The device ofclaim 7, wherein the transparent plate is single and provided with ascratch-resistant coating.
 9. The device of claim 1, wherein theinternal unit is arranged in an inner housing, wherein the inner housingcomprises on a front side, a frame element in which a transparent plateis fixed and wherein the frame element is snapped with a labyrinth sealinto a frame formed by the inner housing.
 10. The device of claim 1,further comprising a focussing element for focussing the scatteredradiation to the pick-up element, wherein the focussing element isformed by a substantially elliptically-shaped mirror element.
 11. Thedevice of claim 10, wherein the focussing element is formed by a goldlayer vapor-deposited on an elliptically-shaped element.
 12. The deviceof claim 10, further comprising an adjusting means for adjusting theelliptically-shaped mirror element relative to the pick-up element. 13.The device of claim 12, wherein the adjusting means comprises aneccentrically arranged pin element which is rotatable into differentpositions and wherein adjustment takes place counter to the action ofresilient holding elements.
 14. The device of claim 1, wherein theinternal unit is arranged in an inner housing, wherein the inner housingseals components of the internal unit in a dustproof manner and whereinthe inner housing is arranged in an outer housing of predefineddimensions.